Tk Source Code

The tk_getOpenFile docs seem outdated and unclear about MacTypes.

The docs say

On the Macintosh platform, a file matches a file pattern if its name matches at least one of 
the extension(s) AND it belongs to at least one of the macType(s) of the file pattern.
For example, the C Source Files file pattern in the sample code matches with files that
have a -c extension AND belong to the macType TEXT. To use the OR rule instead, you can use two
file patterns, one with the extensions only and the other with the macType only. The GIF Files
file type in the sample code matches files that EITHER have a -gif extension OR belong to the
macType GIFF.

On the Unix and Windows platforms, a file matches a file pattern if its name matches at at least
one of the extension(s) of the file pattern. The macTypes are ignored.

I have figured out Macintosh here is not OS X - which is Unix - but OS 9. Which makes the docs obsolete, OS X is 20 years old at this point, and it is using UTIs since around Snow Leopard (around 2006).

I have not figured out what to do on OS X, how to properly call this. It seems the macType is still needed? I have figured out PDFs, for example, used to have four letter code "PDF " (with the space), but I cannot pass that to tk_getOpenFile?

(from tcl ticker: https://core.tcl-lang.org/tcl/info/fd21a14f5c8a5645)

The patch looks fine to me, as far as it goes, but I wonder if there
should be some further edits.  The manual page, even after the changes
that you are proposing, suggests that it might be possible to build the
current version of Tk on a Macintosh OS 9 system. That is not possible.
The current code depends heavily on Cocoa, which did not exist for OS 9.
In the recent discussion about which systems are officially supported
by Tk I was making the case that OSX 10.13 should be the oldest supported
Apple OS.

Yes, the 32-bit "creator code" and "type code" types predate mac OSX.  The
creator code is now ignored wherever it occurs and as far as I know the old
Apple creator code registry is no longer functioning, but still exists in some
undocumented frozen configuration.

The type codes have been essentially (but sort of half-heartedly) replaced
by file extensions in macOS. But the type codes are still supported at some
very low level for some mysterious reason.  The main remnant is that a type
code can be used to specify the official system icon to be used for a
specific file type. 

The Tk code for dealing with file types (along with quite a bit of history
and some discussion of related topics like Uniform Type Identifiers) is
contained in the file tkMacOSXFileTypes.c.  I would recommend starting
with that file if you want to see how type codes fit into Tk and get an
idea of how much work and how much breakage would be involved in removing
them from Tk.

Are type codes causing a problem for anyone, or is this just interesting
because it indicates how long Tk has been around?